This invention relates generally to food casings and is directed more specifically to tubular meat casings coated internally with a material which permits ready and neat removal of the casings from the finished sausages, hams and like meat products encased therein.
As is well known, various foods are preserved by such physical methods as cooling or freezing, thermal processing, drying or dehydration, and treatment by ultraviolet rays or by radiation, or by such chemical methods as the use of chemical preservatives or sterilizers, or of acids or sugar, salting or pickling, and gas substitution. Additional methods of food preservation include the combination of salting and smoking, condensation, thermal seasoning, and pasting.
The food casings to which this invention is directed are intended for use with such preservable food products as sausages or hams which are produced by smoking treatment, or all the above listed methods of food preservation. The casings for sausages or the like are required to serve both as containers during the processing of the products and as protective wrappers for the finished products. In order to fulfill this dual objective, such meat casings are usually fabricated of regenerated cellulose or of fibers including fibrous webs and are provided in the form of tubes which may be creased or uncreased.
For the production of sausages or hams, the desired meat masses are stuffed into the tubular casings and are then smoked at elevated temperatures. The casings must, of course, be removed from the finished meat products prior to slicing. A special problem arises at this juncture in that since the meat masses stick or adhere to the inside surfaces of the casings during their smoking or heating treatment due for the most part to the presence of collagen therein, the casings cannot be peeled off the meat masses without at least parts of the meat masses coming off with the removed casings. This phenomenon greatly impairs the commercial value of such processed meat products.
Thus, in order to improve the "peelability" of the meat casings, it has been proposed to coat their inside surfaces with organosiloxanes or with the reaction product of epichlorohydrine and polyamide, as disclosed in U.S. Pat. Nos. 3,307,956 and 3,158,492, in Japanese Pat. Publication No. 47-11, and in the Japanese patent application laid open to public inspection as No. 48-8959. However, these resins are relatively expensive, and when any excess amounts of the resins are used, they can cause an undue decrease in the necessary permeability of the casings to smoke, moisture vapor, dyeing, and the like. The meat masses encased in this kind of casings cannot be subjected to the smoking treatment with any favorable results.
Another disadvantage of such prior art coatings resides in the fact that they tend to impart too much peelability to the casings. As a consequence, the casings treated with the prior art coating agents are likely to separate in places from the processed meat masses therein, and what are known in the trade as "jelly pockets" may be produced in such unoccupied spaces within the casings. The ultimate result may be the propagation of microorganisms or bacteria therein. It must also be taken into consideration that the aforesaid prior art coatings utilizing organosiloxanes and other resins must be cured at relatively high temperatures, possibly resulting in the impairment of the physical properties of the casings themselves.